Placental characteristics and birthweight
Bibliographic record
Abstract
Standard gross placental measures capture dimensions relevant to specific placental functions. Our objective was to determine their accountability independent of placental weight for variance in birthweight, an important proxy for intrauterine 'adequacy' in fetal origins studies. The sample consisted of 24 152 singleton liveborn children of the Collaborative Perinatal Project delivered from 34 to 42 completed weeks gestation, with complete data for six placental measures (placental disc shape, umbilical cord length, distance from cord insertion to nearest margin, large diameter, small diameter, placental thickness) and placental weight. Associations between birthweight and placental measures were examined using multiple linear regression. Placental weight alone accounted for 36.6% of birthweight variation; the six other placental measures accounted for 28.1%. Combined, all placental measures accounted for 39.1% of birthweight variation. Seven maternal characteristics (age, height, weight, parity, socio-economic status, cigarette use, and race) were investigated to determine whether their known associations with birthweight were mediated by placental markers. Analysis suggested that the impact of all maternal characteristics except smoking was consistent with mediation by placental characteristics.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.013 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".